Transferring a disabled person from a wheelchair to various fixtures or means of conveyance is an extremely laborious physical job that an average person may perform only with difficulty, if at all. During the course of a day, a patient may need to be transferred to a bed, a toilet, a bath, a car, or to various pieces of medical equipment, and, additionally, may require positioning or repositioning once situated on a given fixture or conveyance. The majority of the elderly currently residing in nursing homes or hospitals have been admitted primarily because they can no longer function in their home environment while permanently bedridden. A variety of devices for lifting bedridden persons have been developed and deployed at both homes and hospitals. Many of these devices, however, are awkward, uncomfortable, and often frightening for the elderly. They require direct, physical effort on the part of the caretaker to manually operate, and during transfer, the body may be airborne, tending to swing and rotate, and may cause both discomfort and embarrassment for the patient.
Other examples of direct physical assistance which caregivers may provide include transfer of the patient from one surface to another, positioning of the patient of a surface, changing the clothing and bed sheets of a patient. For example, to prevent bedsores, a caregiver must change the posture of the patient every 3 to 4 hours to maintain blood flow that may be impeded in certain flesh regions for a long period of time. In addition, the posture must be changed to provide stimuli to elderly people with severely debilitated physical activity levels. These tasks which include physical interactions with the bedridden are currently performed by human caregivers. As the population of elderly persons grows, it is desirable that the costly, labor-intensive services described above be provided by the fixture itself.
A human body has numerous degrees of freedom. To successfully transfer a bedridden person to a chair and alter the patient's posture in a natural way by mechanical assistance requires many degrees of freedom. It is difficult to build such equipment using traditional actuators. New technologies are needed to effectively interact with human bodies and perform diverse tasks safely and reliably.